Achieving wipe effect in video with (motion tracked) mask revealing 3D object
If I'm guessing right, you're moving a sheet of paper in a previously taken video to uncover some 3D (extruded) text that's sitting in Blender's 3D window.  

I've done it here with a single animated masking plane.

 

The first example is the (pre-recorded) video I manufactured for the purpose.

The second is the end result when using the first as the bkd video and overlaying it's paper sheet with a matching sized plane. (in Blender's 3D work area)  The plane is textured with a screenshot of the video's paper sheet.

The text is there all the time.  It's the copycat paper (plane) that's hiding it from view.

The plane moves in unison with the video's paper using keyframes and shape keys to match it's changing dimensions as the frames progress.

It is in fact manual tracking and is not difficult in many circumstances.

Once the text is in view, the masking plane is dispensed with and the video can proceed on it's own.

This is but one solution.  Another might be to use Blender's tracking and inbuilt masking.